Process of manufacturing insulating material.



' Patented May 11, 1915 ATTORNEY .J. LONGMQRE.

PROCESS OF MANUFACTURWG WSULATING MATERIAL.

APPLICATION FILED FEB. 6| 1 912.

F/qiZ.

WITNESSES hurrah sra rns Parana: OFF-Ion.

WILLIAM Z5. LONGMORE, OFBELLEVUE, PENNSYLV ANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC ANID MANUFAOTUBING COMPANY, A CORPORATION OF,

PENNSYLVAIIIA.

PROCESS OF MANUFACTURING INSULATING MATERIAL. I

Specification of Letters Patent.

Patented May 11, 1915.-

Application filed February 1c, 1912; Serial No. 678.125.

To all whom it may concern Be it known that I, VILLIALI J. LONG; MORE, a citizen. of the United States, and a resident of Bellevue, in the county ofAllegheuy and State of Pennsylvania, have invented a new and useful Improvement in Processes of ltlanufacturing Insulating Material, of which the following is a specification.

-My invention relates to processes of manufacturing insulating material from flakes or scales of mica, and it has for its object to provide a process whereby built-up sheets or plates of mica of uniform thickness may be produced expeditiously and economically and with the exercise of but little care in the handling.

Plates or sheets of insulating material have heretofore been nninufactured by causing mica scales and pmvdered-binding material to fall in a shower, within a comparatively high tower, upon a plate or support at the lower end of the tower, the mica scales and the binder being thus distributed upon the receiving support with remarkable uniformity. When suflicient mica has, in this 'manner, been deposited upon the receiving plate to provide a finished sheet of the desired thickness, the assembled mica and binder are removed from the lower end of the tower and preliminarily heated and pressed to melt the binder andto cause the mica flakes to adheretogether, and then finally heated for a considerable 1 period while under great pressure in order to press and drive out the excess of the binder and to thoroughly compact the sheet. Owing to the fact that the" flakes of mica and the comminuted binder are deposited ina loose condition upon the receiving plate, it is diflicult to remove the assembled materials from the tower without displacing the same and thereby rendering the plate of non-uni form thickness, or otherwise inpirlng 1t.

According tothepresent lnvention, the flakes of mica and the com'ininuted binder are deposited as above indicated upon a heated plate or support, the heat from which serves to melt the binde and to effect a preliminary cementing together of the mica flakes while the assembledmaterials ar F'llll in the towe so that there is little w'ise'ihjuring the sheet during the removal thereof from the tower.

Figure 1 of the accompanying drawing, is a view, in side elevation and in section, of a part of a suitable tower in connection with which the first step of the present invention is practised,and Fig. 2 is a View, in side elevation, of apparatus for practising the final step of the present process.

In practising the present inventiomloose mica flakes or scales and a comminuted binder, such as dry powdered shellac, are distributed, preferably separately and alternately, in the upper end of a suitable tower 1, and are permitted to fall in a shower from the top to the bottom thereof upon a suitable heated receiving plate or support 2 at the bottom of the tower, the mica flakes being thus entirely disassociated and detached J from each other, and being also uniformly distributed upon the receiving plate.

The receiving plates may be heated outside the tower and placed therein while hot, or, if desired, they may be heated while in the tower by any suitable means, as by providing them with electric heating elements which are preferably embedded or incloscd therein, substantially as indicated in Fi g. 2.. The plates are placed in the tower through a door 3v in its side and are preferably pljaced therein in succession as the desired quantities of mica and shellac are deposited thereon, the new plate being laid, in each case,

upon the loose mica and binder-that has been previously deposited upon the lower plate. The upper plates thus serve as weights to compress the mica scales, while the heat melts the comminuted binder and.

causes the mica flakes to be preliminarily cemented with suflicient security to insure against their displacement during the removalthereof and of the receiving plate from the tower. VVhen'the receiving plates have cooled, the preliminarily cemented mica sheets are of sutlicient strengtlf to permit of their being removed from besheets are next and finally placed in a press and again heated for a considerable period while under heavy pressure for the purpose of driving-out'the excess of binder and of thoroughly compacting the sheets, suitable meansfor efi'ecting this result being shown in Fig. 2.

While it will generally be found preferable to provide a heated plate for receiving the first deposit of commingled mica flakes and oomminuted binding material, the deposit may be made upon a coldplate, if desired since the heat imparted by the second plate and the combined weighti of that and the other superposed plates and layers of mica and binding material will serve to effect such union of the materials as will permit of the handlin the subsequent steps 0 the complete process.

I claim as my invention:

1; The process of manufacturing an insulating sheet which consists in distributing a shower of commingled scales of mica an comminuted dry bond upon a heated member and then applying heat and ressure to the upper surface of said materia while the said material and member are in their original position. 2. The process of manufacturing an insuof ,said distributed material without removwhieh is incident to lating sheet which consists in distributing a an shower of commingled scales of mica an comminuted dry bond upon a plane surface within a. chamber and subsequently applying heat and pressure to the upper surface ing it from the chamber.

3. The process of-manufacturing insulating sheets which consists in distributin showers of commingled scales of mica an a comminuted dry bond upon each of a plurality of successively superposed heated members.

4. The process of making insulating sheets which consists in depositing a shower of commingled mica flakes and comminuted dry binding material upon a plane surface placing a heated plate upon said deposite materials, depositing another shower of said materials upon said heated plate, and applying thereto another heated. plate.

n testimony whereof, hav.e hereunto. subscribed my name this 5th day. of Feb. 1912. I

'WILLIAM J LONGMORE.

Witnesses:

L. A. ARMSTRONG, B. B. Hmns. 

